adding local debugging to docs

docs/my-website/docs/debugging/local_debugging.md

@@ -0,0 +1,57 @@
+# Local Debugging
+There's 2 ways to do local debugging - `litellm.set_verbose=True` and by passing in a custom function `completion(...logger_fn=<your_local_function>)`
+
+## Set Verbose 
+
+This is good for getting print statements for everything litellm is doing.
+```
+from litellm import completion
+
+litellm.set_verbose=True # 👈 this is the 1-line change you need to make
+
+## set ENV variables
+os.environ["OPENAI_API_KEY"] = "openai key"
+os.environ["COHERE_API_KEY"] = "cohere key"
+
+messages = [{ "content": "Hello, how are you?","role": "user"}]
+
+# openai call
+response = completion(model="gpt-3.5-turbo", messages=messages)
+
+# cohere call
+response = completion("command-nightly", messages)
+```
+
+## Logger Function 
+But sometimes all you care about is seeing exactly what's getting sent to your api call and what's being returned - e.g. if the api call is failing, why is that happening? what are the exact params being set? 
+
+In that case, LiteLLM allows you to pass in a custom logging function to see / modify the model call Input/Outputs. 
+
+**Note**: We expect you to accept a dict object. 
+
+Your custom function 
+
+```
+def my_custom_logging_fn(model_call_dict):
+    print(f"model call details: {model_call_dict}")
+```
+
+### Complete Example
+```
+from litellm import completion
+
+def my_custom_logging_fn(model_call_dict):
+    print(f"model call details: {model_call_dict}")
+
+## set ENV variables
+os.environ["OPENAI_API_KEY"] = "openai key"
+os.environ["COHERE_API_KEY"] = "cohere key"
+
+messages = [{ "content": "Hello, how are you?","role": "user"}]
+
+# openai call
+response = completion(model="gpt-3.5-turbo", messages=messages, logger_fn=my_custom_logging_fn)
+
+# cohere call
+response = completion("command-nightly", messages, logger_fn=my_custom_logging_fn)
+```